﻿//
// (C) Copyright 2009 Irantha Suwandarathna (iranthas@hotmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using EffiProz.Core.Lib;
using EffiProz.Core.DataTypes;
using EffiProz.Core.Indexes;
using EffiProz.Core.Errors;
using EffiProz.Core.Persist;

namespace EffiProz.Core
{
    public class ExpressionOrderBy : Expression
    {
        private bool _isDescending;
        private bool _isNullsLast;

        public ExpressionOrderBy(Expression e) :base(OpTypes.ORDER_BY)
        {
            
            nodes = new Expression[UNARY];
            nodes[LEFT] = e;
        }

        /**
         * Set an ORDER BY column expression DESC
         */
        public void setDescending()
        {
            _isDescending = true;
        }

        /**
         * Is an ORDER BY column expression DESC
         */
        public bool isDescending()
        {
            return _isDescending;
        }

        /**
         * Set an ORDER BY column NULL ordering
         */
        public void setNullsLast()
        {
            _isNullsLast = true;
        }

        /**
         * Is an ORDER BY column NULL ordering
         */
        public bool isNullsLast()
        {
            return _isNullsLast;
        }

        public override Object getValue(Session session)
        {
            return nodes[LEFT].getValue(session);
        }

        public override void resolveTypes(Session session, Expression parent)
        {

            nodes[LEFT].resolveTypes(session, parent);

            if (nodes[LEFT]._isParam)
            {
                throw Error.error(ErrorCode.X_42567);
            }

            dataType = nodes[LEFT].dataType;
        }

        public override String getSQL()
        {

            StringBuilder sb = new StringBuilder();

            sb.Append(Tokens.T_ORDER).Append(' ').Append(Tokens.T_BY).Append(' ');

            if (nodes[LEFT].alias != null)
            {
                sb.Append(nodes[LEFT].alias.name);
            }
            else
            {
                sb.Append(nodes[LEFT].getSQL());
            }

            if (_isDescending)
            {
                sb.Append(' ').Append(Tokens.T_DESC);
            }

            return sb.ToString();
        }

        public override String describe(Session session, int blanks)
        {

            StringBuilder sb = new StringBuilder();

            sb.Append('\n');

            for (int i = 0; i < blanks; i++)
            {
                sb.Append(' ');
            }

            sb.Append(Tokens.T_ORDER).Append(' ').Append(Tokens.T_BY);
            sb.Append(' ');

            if (_isDescending)
            {
                sb.Append(Tokens.T_DESC).Append(' ');
            }

            return sb.ToString();
        }
    }
}
